Method of fabricating springs formed of rope pressure-saturated or impregnated with binder

ABSTRACT

A spring consisting of a rope having a plurality of strands each containing a plurality of monofilaments, and a cured binder which has saturated the rope under pressure to cause it to be self-sustaining in spring form. A method of fabricating a spring including the steps of providing a conventional rope composed of a plurality of monofilaments, saturating the rope under pressure with a binder to form a combined rope and binder, forming the combined rope and binder into a predetermined spring shape, and curing the binder to cause the spring to be self-sustaining in the formed predetermined spring shape. A self-damping spring formed by the foregoing method wherein the rope is of the twisted type, and the amount of damping being dependent on the angularity of the twisting. A spring consisting of a first portion of a rope impregnated with binder to hold the spring in a self-sustaining shape and an untreated second rope portion formed integrally with the first portion.

This is a division of application Ser. No. 268,564 filed Nov. 1, 1988,now abandoned, which is a division of prior application Ser. No.928,710, filed Nov. 10, 1986, now abandoned, which is a continuation ofapplication Ser. No. 650,668, filed Sept. 13, 1984, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to improved spring structures formed froma conventional rope which has been (1) either impregnated with a binder(2) saturated with a binder under pressure and to a method offabrication thereof.

By way of background, plastic springs made of epoxy and reinforced byfibers are known, as disclosed in U.S. Pat. Nos. 2,852,424 and4,260,143. However, springs of this type relied on the fibers toreinforce the plastic but, insofar as known, the springs were not formedfrom conventional rope material which was held in spring form by abinder which saturated the rope under pressure. Furthermore, insofar asknown, the prior art did not include a teaching of self-damping springsof the foregoing type fabricated from twisted rope. Also, insofar asknown, the prior art did not include springs made of rope which includeda spring portion impregnated with binder and an untreated rope portionintegral therewith.

SUMMARY OF THE INVENTION

It is accordingly one object of the present invention to provide animproved spring which is fabricated from a conventional commercial ropecontaining monofilaments, with the rope being saturated by a binderunder pressure.

Another object of the present invention is to provide a method offabricating a spring including the step of pressure-saturating a ropewith the binder.

Still another object of the present invention is to provide a method offorming a spring unit consisting of a rope having binder-impregnatedportions and untreated rope portions.

A further object is to provide an improved spring fabricated of apressure-saturated commercial twisted rope which is self-damping, withthe amount of damping being dependent on the angularity of the twistswith respect to the axis of the rope.

Yet another object of the present invention is to provide an improvedspring which is formed of rope, part of which consists of ropeimpregnated with a binder and part of which consists of untreated ropewhich can be used as a tie or hinge.

Still another object of the present invention is to provide an improvedspring support bracket type of device which consists of abinder-impregnated rope portion and an untreated rope portion, thespring bracket being capable of absorbing high and low frequencyvibrations. Other objects and attendant advantages of the presentinvention will readily be perceived hereafter.

The present invention relates to a spring comprising a rope consistingof a plurality of monofilaments, and a cured binder which has saturatedsaid rope under pressure to cause it to be self-sustaining in springform.

The present invention also relates to a method of fabricating a springcomprising the steps of providing a rope composed of a plurality ofmonofilaments, saturating said rope with a binder under pressure to forma combined rope and binder, forming said combined rope and binder into apredetermined spring shape, and curing said binder.

The present invention also relates to a spring comprising a ropeconsisting of a plurality of filaments, and a cured binder impregnatingsaid rope for causing said rope to be self-sustaining in spring form,with said filaments being in twisted form to thereby cause said springto be self-damping.

The present invention also relates to a spring comprising a ropeincluding first portion means impregnated with a binder and formed intoa self-sustaining shape which will provide a spring action, and secondportion means of untreated rope formed integrally with said firstportion means.

The present invention also relates to a bracket for mounting a bodycomprising first rope portion means impregnated with a binder to beself-sustaining, and second rope portion means which is untreated withbinder and which is formed integrally with said first portion means soas to function as a flexible member and for damping low frequencies.

The various aspects of the present invention will be more fullyunderstood when the following portions of the specification are read inconjunction with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary side elevational view of an indeterminate lengthof rope consisting of twisted strands of high strength monofilaments;

FIG. 2 is a schematic view of the rope of FIG. 1 immersed in a bindercontained in a suitable tank to which vacuum is applied;

FIG. 3 is a view similar to FIG. 1 but showing the rope saturated withbinder and being drained;

FIG. 4 is a fragmentary cross sectional view of the saturated rope whichhas been pulled through a suitable tubular sheath;

FIG. 5 is a fragmentary cross sectional view taken in the direction ofarrows 5--5 of FIG. 4 and showing the sheathed rope of FIG. 4 located ina pressurizing chamber;

FIG. 6 is a fragmentary side elevational view of a length of sheathedsaturated rope wound around a suitable mandrel for imparting a springshape to the rope;

FIG. 7 is a schematic view of the mandrel of FIG. 6 with the wound ropethereon being cured in an oven;

FIG. 8 is a side elevational view of the spring removed from the mandrelwith the sheath partially removed from the spring;

FIG. 9 is a fragmentary side elevational view of an alternate form ofrope which can be used to make a spring according to the above-describedprocess;

FIG. 10 is a cross sectional view taken substantially along line 10--10of FIG. 9;

FIG. 11 is a fragmentary side elevational view of another type of ropewhich can be used to make a spring;

FIG. 12 is a cross sectional view taken substantially along line 12--12of FIG. 11.;

FIG. 13 is a fragmentary side elevational view of a rope of the braidedtype;

FIG. 14 is a cross sectional view taken substantially along line 14--14of FIG. 13;

FIG. 15 is a fragmentary schematic cross-sectional view of a device forpracticing a method of impregnating only a section of a rope;

FIG. 16 is a fragmentary schematic cross sectional view of a device forpracticing a method of impregnating spaced portions of a rope withdifferent substances;

FIG. 17 is a fragmentary cross sectional schematic view of a device forpracticing a method of impregnating a sheathed rope with the aid ofultrasonic vibration;

FIG. 18 is a plan view of a sinusoidal flat spring formed according tothe method of FIGS. 1-8;

FIG. 19 is a fragmentary plan view of a section of a sinusoidal flatspring which may be fabricated according to the methods of FIGS. 1-8 orFIG. 15;

FIG. 20 is a fragmentary plan view of a section of a sinusoidal springhaving a shallow curvature which can be pulled to a straight conditionwithout being stressed beyond its elastic limit;

FIG. 21 is a schematic view of the spring of FIG. 20 in a morestraightened condition;

FIG. 22 is a fragmentary plan view of a modified embodiment of thespring of FIG. 19;

FIG. 23 is a cross sectional view taken substantially along line 23-23of FIG. 22;

FIG. 24 is a fragmentary perspective view of a spring which may beformed according to the methods of FIGS. 14 or 15 wherein the spring hasportions which are impregnated with binder, and other portions whichcomprise plain untreated rope;

FIG. 25 is a perspective view of another form of spring of the typeshown in FIG. 24;

FIG. 26 is a perspective view of another form of spring of the typeshown in FIG. 24; and

FIG. 27 is still another form of spring of the type shown in FIG. 24.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 is shown an indeterminate length of circular rope 10 ofcircular cross section. Rope 10 is of any conventional type having hightensile strength. This rope may be twisted, braided or formed in anyother suitable manner of a plurality of strands of high strength plasticmonofilaments which any comprise, without limitation, such filaments asnylon, DACRON or KEVLAR. Preferably the monofilaments are relativelysmall in diameter so as to provide high strength to the rope,considering that the monofilament strength generally varies inversely toits diameter and therefore the strength of the rope varies directly withthe number of monofilaments up to a certain point. In FIG. 1, by way ofexample and not of limitation, rope 10 consists of a plurality oftwisted strands each containing a plurality of monofilaments (FIG. 5).Further by way of example, rope 10 may preferably be of the readilyavailable type known as precision marine rope.

In accordance with the first step of the process, the rope 10 iscombined with a suitable binder to form a combined rope and binder unit11 (FIG. 3) wherein rope 10 is saturated with a binder 12 under pressureto cause the binder to enter all of the spaces between themonofilaments, as well as to also form a layer on the outer periphery ofthe rope. In order to combine the binder 12 with the rope to providesubstantially complete saturation of the latter, the rope is immersed ina tank 13 containing binder 12. Chamber 14 of the tank 13 is evacuatedto produce a reduced pressure in the tank and this will cause theentrained air common in monofilament rope to be withdrawn from betweenthe strands and monofilaments of the rope. Thereafter, the chamber 14 isreturned to atmospheric pressure which will cause the binder 11 to beforced into the voids which sere previously occupied by air between thestrands and monofilaments. Therefore, the foregoing action causes therope to be pressure-saturated with the binder. If desired, aboveatmospheric pressure may be applied to chamber 14 to enhance thesaturation process. Also, if desired vacuum and pressure may be appliedalternately to produce a pumping action. Merely dipping the rope intothe binder will not provide the desired degree of saturation which isobtainable by the foregoing procedures.

After the rope 10 has been saturated with binder 12, it is permitted todrain to remove excess binder, as shown in FIG. 3. Thereafter, thedrained combined rope and binder 12' is pulled through a suitabletubular sheath 15 which may be fabricated of any suitable flexiblematerial such as nylon, polyvinyl plastic, rubber, TEFLON, or any othersuitable material. The flexible tube 15 confines the binder and causesthe rope to retain its saturated condition and shape. The tube 15 alsopermits handling of the saturated rope without the operator beingsubject to contamination or allergic reaction of toxic binders. The tubecan also be used as a diaphragm to which pressure pulses may be appliedto enhance saturation. Furthermore, where the spring is to be inabrasive contact with another body, the tube can be made of soft,abrasive-resistant material to protect the other body and also protectthe saturated rope from notch failure.

An optional further step in the process is to insert tube 15 containingthe pressure-saturated rope 12' into a housing 16 to which high pressurefluid is supplied to the chamber 17 in which the pressure-saturated rope12' has been inserted. The external pressure thus applied will producecompaction of the rope and binder to increase the ratio of filament tobinder to thereby improve the spring strength.

The tube 15 containing pressure-saturated rope 12' is then wound aroundmandrel 19 (FIG. 6) to the desired helical spring shape. If a flatspring or torsion-bar type of spring is being fabricated, then thespring is formed on a suitable fixture.

The next step in the process is to cure the resin and this may be doneby inserting the mandrel 19 with member 15 wound thereon into an oven 20and curing the binder for the proper time at the proper temperature. Ifdesired, the curing may be effected in a pressurized oven to furtherensure that the rope and binder remain compacted and void-free. Sincethe saturating binder encapsulates each of the monofilaments, eachmonofilament is held rigidly within the binder matrix. If the tube 15 ismade of TEFLON or another type of heat-shrinkable material, the step ofcuring the binder under heat will also cause further compaction of thesaturated rope as the tube shrinks.

The final step in the process is to remove the formed spring 18 shown inFIG. 8 from the mandrel and, if desired to remove the sheath 15 inasmuchas the spring is now self-sustaining because of the curing process.

As noted above, the preferred monofilament fibers may be nylon, DACRON,KEVLAR or any other suitable fiber which has the desired fatigue andtensile strength and appropriate modulus of elasticity for the maximumenergy storage or damping action for the application to which the springis to be used. The binder 12 is preferably a suitable epoxy resin orsuitable thermoplastic which has high strength in tension, compressionand fatigue. Other suitable binders may also be used depending on thedesired characteristics of the spring. The finished spring depends onthe strength of the monofilaments, the binder being primarily for thepurpose of holding the monofilaments and spring in the desiredself-sustaining shape while also adding a certain amount of strength tothe spring.

In FIGS. 9 and 10 an alternate embodiment of the type of rope is shownwhich can be formed into a spring of the type disclosed in FIG. 8 afterthe rope has been pressure-saturated with a suitable binder in themanner described above relative to FIGS. 1-7. The rope 22 contains threestrands 23 which are suitably twisted relative to each other, with eachstrand containing a plurality of monofilaments of the type discussed inthe present specification. Wound around strands 23 is a winding 24comprising a single strand also containing a plurality of monofilaments.The winding of strand 24 is at a smaller angle to the longitudinal axis25 than strands 23. In other words, strand 24 extends more nearlyperpendicular to longitudinal axis 25 than strands 23. When the springof FIG. 8 is stressed, the rope 22 will be placed in torsion, as this isa characteristic of a helical spring. The placement of the spring intorsion will be translated to placing both strands 23 and strands 24into tension. However, since strand 24 is more directly in line with andopposing the torsional forces, it will be better able to resist thetorsional forces because monofilaments in strand 24 will be placed intorelatively direct tension along their longitudinal axes and thus thetensile strength of the monofilaments will resist the torsion. Incontrast to this, the monofilaments in strands 23 extend moretransversely to the direction of the torsional forces than strand 24,and therefore while the monofilaments in strands 23 are also placed intension, they are less able to resist the torsional forces because theyare not as much in line with the torsional forces. The sum of thetorsional resistances of the monofilaments in strands 23 and 24constitute the total torsional resistance of the spring, but strand 24greatly adds to the torsional resistance strands 23 because it extendsmore in the direction of the torsional forces.

The monofilaments of strand 24 will provide a very high spring forcebecause they are more able to resist the torsion loading of coilsprings. However, strands 23 provide a damped spring, as set forthhereafter. This combination therefore provides high spring forcesbecause of strand 24, and moderate spring and damping forces because ofmore longitudinally oriented strands 23. The configuration is thereforewell-suited to a vehicle suspension spring in which the moderate dampingwould provide a boulevard ride, removing this requirement from the shockabsorber, which could therefore be made simpler and cheaper.

In FIGS. 11 and 12 a further embodiment of the present invention isdisclosed wherein rope 26 consists of a central strand 27 bounded by abraided sheath 29. Strands 27 and the strands which comprise braidedsheath 29 each comprise a plurality of monofilaments. A strand 30 ishelically wound about braided sheath 29, and strand 30 also contains aplurality of monofilaments. A spring is fabricated from the rope ofFIGS. 11 and 12 in the manner described above relative to FIGS. 1-7. Thestrand 30 acts in the same manner as strand 24 of FIGS. 9 and 10, togreatly increase the resistance of the spring to torsion because themonofilaments of strand 30 extend generally in the direction of thetorsional forces applied to a spring such as shown in FIG. 8. The springof FIGS. 11 and 12 will have less damping than the spring of FIGS. 9 and10, for reasons set forth immediately hereafter.

The spring which is formed from the twisted rope of the type shown inFIGS. 1-8 has been found to exhibit a self-damping characteristic ascompared to the spring 36 of FIGS. 13 and 14 formed of braided strands39 of monofilaments. Spring 36 is formed by the same process as thespring 18 of FIGS. 1-8. The only difference between the two springs isthat one is formed of twisted strands and the other is formed of braidedstrands. The self-damping characteristic causes the spring 18 of FIGS.1-8 formed of twisted rope to have reduced oscillations when subjectedto the same loading as the spring 36, and obviously when compared to ananalogous metal spring. The amount of damping of a twisted rope springis directly proportional to the angle of the twist, that is, the moreperpendicular the twist to the longitudinal axis of the rope, the morethe damping. It is believed that the lesser damping capability of thebraided rope of FIGS. 13 and 14 is due to the high lead angle of thefilaments, and this causes the spring to have relatively little damping,which makes it better suited to high speed or high energy outputrequirements.

By way of example and not of limitation, springs have actually beenformed from the following. Conventional twisted rope known as precisionmarine rope was used having an outer diameter of 1/4 inch. The ropeconsisted of nine strands each containing approximately sevenmonofilaments each having a diameter of approximately 0.006 inches, themonofilaments being of DACRON polyester. The binder was epoxy resin ofthe type known as a high temperature, low-viscositycycloaliphaticpolyamine. Other binders of the type described in Pat. No.4,260,143 may also be used. The pressure saturation was effected byimmersing the rope in the binder and subjecting the binder to a suitablehigh vacuum, and thereafter returning the binder to atmosphericpressure. The pressure-saturated rope was pulled through a plasticsheath having an internal diameter equal to the outer diameter of therope. The sheathed saturated rope was cured in an oven at 80° C.-132° C.for four hours. The resulting spring exhibited satisfactory springcharacteristics. Springs were also made of ropes of nylon and KEVLAR ofsizes of 5/16, 3/8 and 1/2 inches.

In the spring which was formed as set forth in the foregoing paragraph,the rope comprised 75% of the spring by volume and the binder comprised25% by volume. By weight, the spring comprised 65% rope and 35% binder.

It is to be noted that the helix of the spring is fabricated in such adirection relative to the direction of the strands that when the springis stressed, the torsional effect on the spring material places themonofilament fibers in tension.

In FIG. 15 there is a schematic showing of a device 40 and method forsaturating only a section 42 of rope 43 while leaving the end portions44 in their normal unsaturated state so that they can function as ropes(see FIG. 19). Device 40 includes a housing 46 having a bore 48 oflesser diameter than rope 43. Rope 43 is pulled through bore 48 so thatit is compressed therein. If desired, housing 46 may be made in twosections. Vacuum tubes 50 draw a vacuum on the portion of rope 42 withinhousing 46. Simultaneously a measured charge of epoxy or other binderfrom cartridge 52 is injected directly into central rope portion 42 byneedle 54 which penetrates the rope. The vacuum which is applied throughtubes 50 will draw the binder through a portion of rope 42. Theforegoing injection process may be carried out to complete saturationfor optimum results, or, if desired to have less than completesaturation, the portion 42 of the rope may be impregnated to any desiredextent. However, it is preferable that there be complete saturation. Therope 43 which is treated in the foregoing manner is then formed to asuitable shape and cured as discussed above relative to FIGS. 1-8.However, the forming is to any desired shape and not necessarily helicalas described above. The manner in which partially treated ropes, such as43, are formed will be described hereafter.

In FIG. 16 another device 56 and method are schematically shown fortreating a rope 58 with different materials at different portions of itslength. In this respect, the portion 60 of the rope is treated in adevice, such as 46, wherein vacuum is applied through tubes 50 and asuitable binder is injected directly into the rope through needle 54which penetrates the rope as described above. Another device 46' whichmay be analogous to device 46 has vacuum tubes 50' and a needle 54'. Theportion 62 of the rope is injected with another substance, such asNEOPRENE. The portions 64, 66 and 68 of the rope remain untreated.Thereafter, the treated rope 58 is formed to any suitable shape andcured. If desired, the treated portions 62 and 60 of rope 58 may be inimmediate abutting relationship with no section of untreated ropetherebetween.

In the embodiment of FIG. 17, rope 68 is located within a tube 46a whichis considered a housing. The rope 68 may be impregnated within the tube46a by inserting needles 50" to create a vacuum in the space in rope 68between the needles and by directly injecting a suitable binder into therope through needle 54 which penetrates the rope so that portion 72between needles 50' becomes impregnated with binder. A suitable vibrator70, which may be of the ultrasonic type or any other type, is placedagainst tube 46a to aid in the impregnating process. Alternatively, anultrasonic vibrator, such as 70, may be spaced a distance from tube 46a.Tube 46a may be a suitable plastic tube of the type described aboverelative to FIG. 4. Yet another alternate is the use of a microwaveelement to oscillate the molecular structure of the fibers to assure thedesired degree of impregnation while the heat generated cures thebinder.

In FIG. 18 a sinusoidal spring 74 is shown which is fabricated accordingto the method of FIGS. 1-8. The sinusoidal spring is saturatedthroughout its length and is formed in a suitable die in which it iscured. The ends 75 of the rope are formed into eyelets for receivingsuitable pins or screws.

In FIG. 19 a sinusoidal spring 77 is shown which is formed according tothe method described above relative to FIG. 15. Spring 77 includes endportions 79 formed of untreated rope of the above-described types. Theuntreated portions terminate at boundaries 80. The untreated portions 79may be of any arbitrary length so that these portions can function asties for attaching the spring to other objects, or the untreatedportions can function as hinges. The central portion 81 betweenboundaries 80 is treated in the manner described above relative to FIG.15. The central portion 81 is also formed in a suitable die which mayhold it during the curing operation. At this juncture it is to be notedthat central portion 81 is preferably completely saturated, or ifdesired, it may be impregnated to any desired extent less thansaturation. At this point, it is to be noted that impregnation isdefined as containing sufficient binder to cause the spring to beself-sustaining, and that saturated is defined as containing a maximumamount of binder between the strands and monofilaments, and pressuresaturation is defined as saturating the rope under pressure.

In FIG. 20 a section of spring 83 is shown which may be either of thetype shown in FIG. 18 or FIG. 19. The central treated portion 84, whichcontains cured binder which either saturates or impregnates it, is ofless curvature than the springs shown in FIGS. 18 and 19. As can be seenfrom FIG. 21, when forces 85 are applied to the central portion 84, thebinder at convex portions 86 is placed in compression and the binder atconcave portions 87 is placed in tension. When forces 85 are released,stresses are applied to the binder at areas 86 and 87 to return thespring 83 to its original unstressed form shown in FIG. 20. Thecharacteristic of a spring having a shallow curvature, such as shown inFIG. 20, is that it can be pulled to a straight condition and the forcesapplied to it will be resisted by the strength of the filaments of therope itself so that if the forces 85 are greater than the elastic limitof the binder but are not of a magnitude which will stretch the rope,the spring will always return to its original unstressed state whenforces 85 are removed.

In FIGS. 22 and 23 a modified form of the spring of FIG. 19 is disclosedwherein the treated sinusoidal portion 81' is encircled by a metal coilspring 89 which will act as a conductor to dissipate heat.

In FIGS. 24-27 various forms of springs are disclosed which may befabricated according to the methods disclosed above relative to FIGS. 15and 16. Spring 74 includes lower leg portions 75 and 76. Lower legportion includes portions 77, 79 and 80 which comprise rope which hasbeen impregnated with a suitable binder. Lower portion 76 includesportions 81, 82 and 83 which have been impregnated with a suitablebinder. The impregnation can be effected in any suitable manner andpreferably by the method set forth above relative to FIG. 15. The springalso includes an upper portion 84 consisting of portions 85, 86 and 87which are impregnated with a suitable binder. Joining portions 85 and 80is a segment 89 of rope which has not been impregnated. Joining portions83 and 87 is a rope portion 90 which also has not been impregnated. Theimpregnated portions of the spring 74 have normal spring characteristicsso that they can flex to absorb forces of a certain magnitude andfrequency. However, the portions 89 and 90 which are not impregnatedwill act as soft columns to absorb high frequency oscillations and otherforces. Thus, the impregnated and plain portions of the spring absorb amultitude of forces of different magnitudes and frequencies. Inaddition, the spring 74 is an insulator so that it electricallyinsulates the supported body 91 from base 92. A bracket 93 isschematically shown as attaching leg portions 82 and 75 to base 92.Another bracket 94 is shown as attaching spring portion 86 to theunderside of body 91. Body 91 may be a chassis of an electronicstructure or any other body. The fastenings between bracket 93 and base92 and between body 91 and bracket 94 have been omitted in the interestof clarity.

In FIG. 25 another form of spring 95 is shown between base 96 and body97. Spring 95 includes leg portions 99 and 100. Leg portion 99 includesparts 101, 102 and 103. Leg 100 includes portions 104 and 105. Legs 99and 100 are impregnated with suitable binders or rubber or a combinationof both and function as springs as described above. Spring portion 106includes central portion 107 and outer portions 109 and 110 at oppositeends thereof. Spring portion 106 is also formed of rope impregnated withbinder. An untreated portion of rope 111 connects spring portions 100and 110. An untreated rope portion 112 connects spring portions 99 and109. Suitable brackets 113 and 114 connect leg portions 101 and 104,respectively, to base 96. A bracket 115 connects the underside of bodyportion 97 to spring portion 107. The fasteners for brackets 113, 114and 115 have been omitted in the interest of clarity. As noted aboverelative to the embodiment of FIG. 24, the impregnated portions 99, 100and 106 of the spring have normal spring characteristics. The untreatedportions 11 and 112 of the spring are ropes which have greatflexibility. It can thus be seen that the spring 95 is capable ofsupporting body 97, which may be an electronic chassis, against forcesof low and high magnitude as well as vibrations of both high and lowfrequency. Untreated rope portions 111 and 112 are in tension, ascompared to rope portions 89 and 99 of FIG. 24 being in compression.

In FIG. 26 another form of spring 117 is shown which includesimpregnated leg portions 119 and 120 connected by an untreated ropeportion 121. The impregnated leg portion 119 includes portions 122, 123and 124. Leg portion 120 includes portions 125, 126, 127 and 128. It isportions 124 and 128 which are connected by untreated rope portion 121.Leg portions 122 and 125 are intended to be secured to a base andportion 128 is intended to be secured to a body by means of bracket 129.As with the embodiments of FIGS. 24 and 25, the spring of FIG. 26 willsupport a body against loads of high and low magnitude and high and lowfrequency.

In FIG. 27 a combined hanger and spring 131 is shown wherein animpregnated portion 132 is connected to an untreated rope portion 133and an impregnated eyelet 134 is attached to untreated portion 133.Portion 132 includes a circular portion 135 which is connected to astraight portion 136 which is connected to untreated rope 133. A screw137 connects eyelet 134 to a suitable post 139 which extends outwardlyfrom a wall or the like. The spring 131 is intended to be used as ahanger for pipe 140. It can be seen that rope portion 133 remainsflexible and is loaded in tension so that it will permit pipe 140 toswing sideways while the impregnated portions 134 and 135 willresiliently support pipe 140.

Only certain representative configurations have been shown in FIGS.24-27, but it will be appreciated that springs can be made in anydesired form whatsoever and that the present invention is not limited tothe forms shown in FIGS. 24-27. The basic underlying characteristic ofsprings, such as shown in FIGS. 24-27, is that they are a composite ofone or more portions of untreated rope and one or more portions whichmay be saturated or impregnated with a cured binder.

In the embodiments of FIGS. 24-27 the rope functions as an integral partof the spring and acts either as a column in compression (FIGS. 24 and26) or acts as a link in tension (FIGS. 25 and 27). Furthermore, in FIG.19, the untreated portion of the rope can act as a member to tie theremainder of the spring to an external body, in which event it acts intension.

In the embodiments of FIGS. 19, 22 and 24-27, the parts of the springwhich contain cured binder may either be formed by a process wherein thebinder pressure saturates certain portions of the spring or the bindermay merely impregnate these portions of the spring. The pressuresaturation is meant to include the complete saturating of the parentrope under pressure, as discussed above, either by applying a vacuum andthereafter subjecting the evacuated rope to pressure, whereas theimpregnation of the rope is meant to mean merely placing enough binderinto portions of the spring to cause it to be self-sustaining and notnecessarily be pressure-saturated. The term "impregnate" is intended tobe broader than the term "saturate" in the sense that a rope which is"impregnated" may have any amount of binder up to and including being"saturated." In other words, being "saturated" is a specific embodimentof being "impregnated."

It will further be appreciated that under certain circumstances theratio of binder to rope in the embodiments of FIGS. 24-27 may be such asto cause the impregnated portions to be substantially rigid, rather thanto provide a spring action. In such circumstances, the flexiblesupporting capability of the brackets shown in these figures will resultonly from the untreated rope portions.

The embodiments of FIGS. 24-27 may be made in any number of differentways. One way would be to form them in dies which have cavities of theform of the finished spring and to inject binder at select portions ofthe die while avoiding injection in other portions of the die. Anothermethod could be by forming the springs in a plurality of steps by aplurality of dies which treat different portions of the spring. The dieswhich are used can also contain heating means for curing the impregnatedrope portions. In addition to the foregoing, the impregnated ropeportions are preferably encased in tubes, such as shown in FIG. 4.However, with dies in which the binder is injected into the rope, in themanner shown in FIG. 15, a tubular sheath need not be used.

While preferred embodiments of the present invention have beendisclosed, it will be appreciated that the present invention is notlimited thereto but may be otherwise embodied within the scope of thefollowing claims.

What is claimed is:
 1. A method of fabricating a spring comprising thesteps of applying vacuum to a portion of a conventional preformed ropeof plastic material having an outer surface defining an internalportion, injecting a binder directly into said internal portion of saidportion of said rope within said outer surface by needle means whicheffect a penetration of said internal portion within said outer surface,forming the injected conventional preformed portion of said rope into aspring shape, and curing said binder.
 2. A method of fabricating aspring as set forth in claim 1 including the step of leaving a portionof said conventional preformed rope in its original form so that thisportion of the spring in its final form does not contain said injectedbinder.
 3. A method of fabricating a spring as set forth in claim 1including the step of confining the portion of the conventionalpreformed rope which is subjected to vacuum in a form.
 4. A method offabricating a spring as set forth in claim 1 wherein said portion ofconventional preformed rope is located in a sheath, and wherein saidvacuum is applied into said internal portion of said portion ofconventional preformed rope by needle means which effect a rupturingpenetration of said outer surface of said conventional preformed ropeand said sheath.
 5. A method of fabricating a spring as set forth inclaim 1 wherein said portion of said conventional preformed rope islocated in a housing, and wherein said vacuum is applied into saidinternal portion of said portion of said conventional preformed rope byneedle means which effect a rupturing penetration of said outer surfaceof said conventional preformed rope.
 6. A method of fabricating a springas set forth in claim 1 wherein said conventional preformed rope isfabricated of aramid.
 7. A method of fabricating a spring comprising thesteps of applying vacuum to a conventional preformed rope of plasticmaterial having an outer surface defining an internal portion, injectinga binder directly into said internal portion of said rope within saidouter surface by needle means which effect a penetration of saidinternal portion within said outer surface, forming the injectedconventional preformed rope into a spring shape, and curing said binder.8. A method of fabricating a spring as set forth in claim 7 includingthe step of leaving a portion of said conventional preformed rope in itsoriginal form so that this portion of the spring in its final form doesnot contain said injected binder.
 9. A method of fabricating a spring asset forth in claim 7 including the step of confining said conventionalpreformed rope which is subjected to vacuum in a form.
 10. A method offabricating a spring as set forth in claim 7 wherein said conventionalpreformed rope is located in a sheath, and wherein said vacuum isapplied into said internal portion of said conventional preformed ropeby needle means which effect a rupturing penetration of both said sheathand said outer surface of said conventional preformed rope.
 11. A methodof fabricating a spring as set forth in claim 7 wherein saidconventional preformed rope is located in a housing, and wherein saidvacuum is applied into said internal portion of said conventionalpreformed rope by needle means which effect a rupturing penetration ofsaid outer surface of said conventional preformed rope.
 12. A method offabricating a spring as set forth in claim 7 wherein said conventionalpreformed rope is fabricated of aramid.